Date: Mar 14, 2013 7:13 AM
Author: Roger Wilson
Subject: Multiple independent random number streams cannot be implemented.

Hopefully the title is enough of a red flag for someone to try to prove me wrong.

I want to implement two functions; lets call them f and g so that they both return random numbers. For example...


However I want f and g to return the same number when they're called for the nth time. So the first call to f is always the same number and the first call to g is always the same number.

In the above case (on my machine)...
SeedRandom[1]; {f[], g[]} gives {0.168697, 0.113119}

and of course..
SeedRandom[1]; {g[], f[]} gives the same {0.817389, 0.11142}

Essentially I want f and g to to be independent random sources.

It is possible to localize the random number generators using BlockRandom but I do not see how that helps me in this case. BlockRandom localizes the state of the random number generators within the block where as I want to localize them into the symbol names.